Drones were spotted hovering over Paris landmarks for a second straight night — and French police are still scratching their heads as to who could be behind the mysterious flyovers.

Parisian officials said Wednesday that witnesses and security forces reported at least five sightings of unmanned aerial devices between midnight and 6 a.m. over sensitive and well-known sites across the city, AFP reported.

The aircraft were seen flying above the US Embassy, the Eiffel Tower, Place de la Concorde, and the Invalides military museum — which were all targets of mystery flyovers the night before. They were also spotted at the Porte de Clignancourt and Porte de Saint-Cloud, which are heavily traveled transport gates leading in and out of Paris.

While officials have said the drones currently pose no threat, French authorities launched a probe this week to try to determine whether the overflights could be more sinister in nature.

Drones similar to this one have been spotted flying over Paris for two straight nights.AP

“Is it a game? Scouting for future operations? The investigation will show us,” a Parisian police chief told AFP.

In recent months, unmanned UFOs have been making flights over some of the most highly protected sites in France — including the home of French President Francois Hollande, several atomic power plants and a series of military facilities housing nuclear submarines. An estimated 20 flyovers took place between October and November, officials said.

Operating a drone over the French capital at night is illegal and the latest sightings come less than two weeks after Islamic terrorist attacks on the satirical magazine Charlie Hebdo and a kosher grocery store left 16 people dead and had the nation on edge for three days.

“Many sensitive sites are protected and from now on we are asking law enforcement to have an eye on the sky as well,” a police source explained to AFP.

Speaking at a news briefing Wednesday, French government spokesman Stephane Le Foll urged people to remain calm while authorities try to find out who is flying the drones and why.

“There is nothing to worry about,” he explained. “Drones have been spotted and investigations launched. We are mobilized on a matter which is and should be taken seriously.”